The present invention relates to a method and apparatus for controlling an open-end spinning frame and, more particularly, to a method and apparatus for controlling a fiber feed machanism for starting and stopping of the spinning frame as well as for controlling to stop the same when there take place breakage of yarn.
An open-end spinning frame, in general, includes a plurality of spinning units. In each of these units, a bundle of fibers or a carded tape supplied from a fiber bundle supply device such as feed rollers is opened by the virtue of a opening device such as combining roller to provided discrete fibers, which are then fed into a gathering and twisting device of a rotary spinning chamber to form a yarn which, in turn, is drawn out of the aforesaid gathering and twisting device through a yarn guide pipe in the cooperation with a draw-off roller and a top roller rotating in contact therewith, the yarn being turned over the periphery of a bobbin held in pressure contact with a take-up roller, to thereby form a cheese.
In the prior open-end spinning frame of the type described, the driving system for fiber bundle feed mechanisms is constructed such that a driving power is in turn transmitted from a drive motor to a gear train, a feed roller driving shaft common for use with all the spinning units, a main electromagnetic clutch mounted on the aforesaid driving shaft, a common interlocking shaft, an auxiliary electromagnetic clutch in each spinning unit and a feed roller in each spinning unit, in this order. As a result, at the time of a starting operation of the spinning frame, the aforesaid main electromagnetic clutch is actuated by an electric control device and the like in the course of yarn ending operation so as to couple the interlocking shaft to the driving shaft whereby the feed roller in all the spinning units may simultaneously commenced to be rotated for starting the feeding of loosened fibers into rotary spinning chambers. When breakage of yarn takes place in any spinning unit during spinning operation, the auxiliary electromagnetic clutch in the spinning unit, in which yarn breakage took place is individually actuated to release only the feed roller in the aforesaid spinning unit from the engagement with the interlocking shaft, thereby interrupting fiber supply in the aforesaid unit, and when the operation of the spinning frame is to be terminated, the main electromagnetic clutch is switched off to release the interlocking shaft from the engagement with the driving shaft while an electromagnetic brake provided at an end of the interlocking shaft is actuated to brake the interlocking shaft, thereby simultaneously stopping all the feed rollers in respective spinning units.
The prior open-end spinning frame has, however, suffered from the disadvantages in that, because of its construction in which, upon starting and stopping the operation of the spinning frame, the main electromagnetic clutch provided between the driving shaft and the interlocking shaft is actuated and switched off to simultaneously commence and stop rotation of all the feed rollers in the spinning units together with the interlocking shaft, there tended to take place considerable twists or distorsion in the interlocking shaft extending over the length of the open-end spinning frame, particularly at the time where all the feed rollers are commenced to turn simultaneously by the actuation of the main electromagnetic clutch. This distortion of the interlocking shaft leads to the fact that, at the end of the interlocking shaft adjacent to the driving shaft, there results sufficiently synchronized starting of rotation between the interlocking shaft and driving shaft, while the other end of the interlock shaft remote from the driving shaft irregularly starts rotation in a delayed timing to the driving shaft, whereby the starting timing of the feed rollers located remote from the driving shaft becomes irregular, thereby preventing smooth operation of yarn ending. Further, a large inertia tends to act on the interlocking shaft due to the moment of rotation of the feed rollers which is produced when the main electromagnetic clutch is disengaged to simultaneously stop all the feed rollers together with the interlocking shaft. Such inertia, unless there is employed an electromagnetic brake adapted to effect braking of the interlocking shaft as in the prior art construction above described, will make it impossible to simultaneously stop all the feed rollers in respective spinning units in such a manner as to leave the end of yarn in respective yarn guide pipes, and thus the provision of such an electromagnetic brake leads to considerable complexity in the driving and controlling arrangement.